He was a Labour Party Member of Parliament for over 41 years, from 1959 to 2001, which included a period as Secretary of State for Wales from 1974 to 1979 and as Attorney General between 1997 and 1999.

[5] He was also the last surviving member of Harold Wilson's 1974–76 cabinet, and was the longest-serving Privy Counsellor at the time of his death.

As such, he was one of only a small handful of Labour ministers to hold office under Harold Wilson, James Callaghan and Tony Blair.

He succeeded fellow Labour politician Lord Merlyn-Rees as the Chancellor for the University of Glamorgan.

[7][9][17] Morris was raised to the peerage for life as Baron Morris of Aberavon, of Aberavon in the County of West Glamorgan and of Ceredigion in the County of Dyfed in the 2001 Dissolution Honours,[18][19] was made Lord Lieutenant of Dyfed a year later[20] and was appointed to the Order of the Garter as a Knight Companion (KG) in 2003.